California Code, Business and Professions Code - BPC § 2538.33

(a) Before engaging in the practice of fitting or selling hearing aids, each licensee shall notify the board in writing of the address or addresses where they are to engage, or intend to engage, in the practice of fitting or selling hearing aids, and of any changes in their place of business within 30 days of engaging in that practice.

(b) If a street address is not the address at which the licensee receives mail, the licensee shall also notify the board in writing of the mailing address for each location where the licensee is to engage, or intends to engage, in the practice of fitting or selling hearing aids, and of any change in the mailing address of their place or places of business.